Televison camera

In a television camera having an optical system, an iris device, an automatic iris control device for automatically controlling opening of said iris device, a photoelectric conversion element for converting an optical image obtained through said optical system and said iris device into an electric signal, a first detection means responsive to flickering in the electric signal at an output of said photoelectric conversion element for detecting flickering at a flickering frequency of a first illumination light source, each half cycle of the flickering frequency defining a flickering period, a signal storage time control means for controlling a signal storage time of said photoelectric conversion element such that in response to the first detection means detecting the flickering, the signal storage time is controlled to become an integer multiple of the flickering period of said firs light source, whereby changing the signal storage time to an integer multiple of the flickering period substantially eliminates flicker in the electric signal at the output of the photoelectric conversion element, THE IMPROVEMENT COMPRISING:

• a second detection means including:
• a means for storing a color temperature information value in response to said first detection means detecting the flickering frequency,
• a means for comparing subsequent color temperature information values with said stored color temperature information, and
• a means connected with the signal storage time control means for causing the signal storage time control means to change the signal storage time of said photoelectric conversion element from the integer multiple of the flickering period to a predetermined time different from the integer multiple of the flickering period in response to said comparing means detecting the change of color temperature information values exceeding a preselected minimum change indicative of a switching from said first light source to another light source.

A television camera having flicker noise restriction capability, which camera includes a lens system, an iris device, a photoelectric conversion element disposed behind said iris device for converting an optical image received through said lens system and said iris device into an electric signal, an iris control device, a variable gain circuit for regulating gain of said photoelectric conversion element and a signal processing circuit for processing the electric signal from said photoelectric conversion element to obtain a television signal, said television camera comprising:

• first means responsive to an output signal of said signal processing circuit to supplying control signals for controlling said iris control device and said variable gain circuit;
• an integrater circuit for integrating the television signal for a time corresponding to one field period and sampling and holding an integrated television signal every field;
• second means responsive to an output of said integrater circuit for determining whether or not there is flicker noise;
• third means for regulating signal storage time of said photoelectric conversion element to 1/100 sec and storing an iris value and a gain when said second means determines existence of flicker noise;
• fourth means responsive to an iris value and a gain for determining whether or not there is any change in iris value and gain when said second means determines absence of flicker noise;
• fifth means for changing signal storage time of said photoelectric conversion element to 1/60 sec when said fourth means determines an existence of change of iris value and gain.